JP4874587B2 - Float type drain trap - Google Patents

Description

  The present invention relates to a float drain trap used for automatically discharging drain in compressed air.

As shown in FIG. 2 or FIG. 3, the float drain trap has a drain valve 3 that opens and closes the discharge port 2 of the drain case 1 attached to a piston 5 housed in a cylinder 4, and pilot air pressure is applied to the piston 5. A pilot valve mechanism that opens the drain valve 3 by operating is provided, and the pilot valve 7 of the pilot valve mechanism is opened and closed by a lifting and lowering operation of the float 6 disposed outside the cylinder 4.
In this case, most of the conventional float drain traps as shown in FIG. 2 or FIG. 3 adopt a system in which the pilot valve 7 is directly opened and closed by the buoyancy of the float 6. In this system, the float 6 Since the mechanism that transmits the movement of the pilot valve 7 to the pilot valve 7 is exposed and the filter 10 cannot be attached to this portion, it is not possible to prevent the entry of harmful foreign substances into the pilot valve 7, and the pilot valve 7 is clogged. Troubles such as air leaks due to malfunctions and foreign object biting into the pilot valve 7 were not constant.

  Further, in the conventional float drain trap, since the pilot valve 7 is directly operated by the movement of the float 6, it is difficult to obtain the snap action of the pilot valve 7, and the pilot valve 7 and the drain valve 3 are in a half-open state. There was a bug.

  Furthermore, in the conventional float type drain trap, since the pilot valve 7 is directly operated by the movement of the float 6, the control method of the pressure in the pilot chamber 8 by opening and closing the pilot valve 7 is controlled by opening the pilot valve 7. Since the air pressure is supplied to the chamber 8 and a part of the air pressure is discharged from the orifice 9 to generate a pressure difference, the diameter of the pilot valve 7 needs to be considerably larger than the diameter of the orifice 9. Therefore, the float 6 for operating the pilot valve 7 also requires a large one.

  A mechanism for amplifying the float buoyancy of the lever, lever 16 or the like at the connecting portion between the float 6 and the pilot valve 7 is employed as a means for making the float 6 as small as possible to compensate for the drawback of the float 6 becoming large. However, since the configuration is complicated, it often breaks down due to the failure of the connecting portion.

  In view of the problems of the above-described conventional float drain trap, the present invention prevents foreign matter from entering the pilot valve by providing a filter in the pilot air pressure introduction path supplied to the pilot valve through the orifice. In addition, the pilot valve is operated indirectly from the outside by using magnetic force, and stability and snap action function are provided to the pilot valve. An object of the present invention is to provide a float drain trap that can reduce the diameter of the pilot valve and the float as much as possible by adopting a pilot air pressure control system disposed upstream of the pilot air.

In order to achieve the above object, the float drain trap of the present invention has a drain valve for opening and closing the drain port of the drain case attached to a piston housed in the cylinder, and in addition to the biasing force of the spring, a pilot valve A float drain trap having a pilot valve mechanism that opens and closes a drain valve by applying air pressure, and that opens and closes the pilot valve of the pilot valve mechanism by lifting and lowering a float disposed outside the cylinder. The pilot valve mechanism opens and closes a valve seat disposed in the pilot chamber, and in an open state, the pilot chamber is communicated with the outside of the drain case, thereby allowing air in the pilot chamber to pass through the exhaust pipe. A pilot valve to be discharged and formed on the upstream side of the pilot valve; An inner casing and communicating, annexed an orifice for introducing the air pressure in the drain bowl in the pilot chamber, as well as configuration and a filter attached to the top of the orifice, a permanent magnet in the pilot valve, wherein When the float is at the lowermost end, the float is positioned below the permanent magnet of the pilot valve, and an attractive force acts between the permanent magnet to urge the pilot valve in the closing direction, and the float rises. then, characterized by being attached to the permanent magnet opening operation instantaneously pilot valve repulsive force acts between the permanent magnet approaching from below the permanent magnet of the pilot valve.

According to the float type drain trap of the present invention, the pilot valve can be indirectly operated by the magnetic force acting between the permanent magnet attached to the pilot valve and the permanent magnet attached to the float.
In the state where the float is at the lowermost end, the pilot valve is urged in the closing direction by the action of the attractive force of the two magnets, and the repulsive force of the two magnets is proportional to the lift amount of the float. As the pressure rises, the repulsive force of the magnet gradually increases, and when the repulsive force exceeds the back pressure acting on the pilot valve, the pilot valve opens instantaneously, and when the pilot valve opens, the back pressure decreases and floats. The float rises further and the snap action function that ensures full opening of the pilot valve can be provided, which enables stable drainage over a wide operating pressure range from low pressure to high pressure. be able to.
In addition, since this float type drain trap operates the pilot valve indirectly by magnetic force, the orifice and the filter can be provided in the pilot air pressure introduction path upstream of the pilot valve, which is harmful to the pilot valve. Intrusion of foreign matter can be prevented and pilot valve failures caused by foreign matter entry can be eliminated.
By arranging the orifice upstream of the pilot valve, the diameter of the pilot valve can be reduced to the same extent as the orifice, and as a result, the float can be reduced.
Also, with the conventional float drain trap, the pilot air pressure control system is limited, so the drain valve system must be the spool valve system, and the spool valve system increases the stroke between the piston and drain valve. Although the drain valve may be damaged in a short period of time, in the float type drain trap of the present invention, it is possible to adopt the poppet valve method because the choice of the control method of the pilot air pressure has increased. In the system, the failure of the drain valve can be reduced because the valve structure is simple and the stroke can be shortened.
In the conventional float drain trap, a mechanism for connecting the pilot valve and the float is necessary. Therefore, the malfunction may occur due to the malfunction of this mechanism. In the float drain trap of the present invention, however, This type of failure can be eliminated because no special mechanism is required.

  Embodiments of the float drain trap of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the float drain trap of the present invention.
In this float drain trap, a drain valve 3 that opens and closes a discharge port 2 of a drain case 1 is attached to a piston 5 accommodated in a cylinder 4, and a pilot air pressure is applied to the piston 5 to open the drain valve 3. A pilot valve mechanism is provided for opening and closing, and the pilot valve 7 of the pilot valve mechanism is opened and closed by the lifting and lowering operation of the float 6 disposed outside the cylinder 4.
In this float drain trap, the pilot valve mechanism is disposed in a part of the pilot chamber 8. The pilot valve 7 communicates the pilot chamber 8 with the outside of the drain case 1, and the upstream of the pilot valve 7. And is provided with an orifice 9 that communicates between the pilot chamber 8 and the inside of the drain case 1 and a filter 10 (preferably a fine filter) attached to the orifice 9. A permanent magnet 11 is attached, and a permanent magnet 12 that repels the permanent magnet 11 and operates the pilot valve 7 is attached to the float 6.

The drain case 1 is installed in a compressed air pipe or the like, and a drain discharge port 2 is provided at the center of the bottom thereof.
A cylinder 4 is fixed on the discharge port 2, and a piston 5 is accommodated inside the cylinder 4 so as to be movable up and down.
The piston 5 is urged downward by a spring 13 disposed thereon, and the drain valve 3 attached to the tip closes the valve seat 21 of the discharge port 2.
When the pilot valve 7 is opened and the pilot chamber 8 is opened outside the drain case 1, the piston 5 is pushed up by the pressure in the drain case 1 to open the drain valve 3.
The spring 13 is an auxiliary one for reliably closing the drain valve 3 after draining.

A pilot chamber 8 in which pilot air pressure acts is partitioned by a piston 5 inside the cylinder 4.
The pilot chamber 8 forms a small chamber 82 communicating with the upper portion of the cylinder 4 via a communication passage 81, and the pilot valve 7 is disposed in the small chamber 82.
The pilot valve 7 opens and closes a valve seat 71 formed at the bottom of the small chamber 82. When the pilot valve 7 is open, the pilot chamber 8 communicates with the outside of the drain case 1, thereby allowing air in the pilot chamber 8 to pass through the exhaust pipe 72. Discharged through.
A ring-shaped permanent magnet 11 that repels the permanent magnet 12 of the float 6 is fixed to the outer periphery of the pilot valve 7.
An orifice 9 is formed on the upper wall of the small chamber 82 to communicate the pilot chamber 8 and the inside of the drain case 1. A filter 10 and a filter cover for protecting the filter 10 are provided above the orifice 9. 14 are installed.
The exhaust pipe 72 extends through the piston 5 to the discharge port 2, and a packing 15 is disposed on the sliding portion of the piston 5.
The filter 10 is made of a mesh net that is sufficiently smaller than the hole diameter of the orifice 9 and the valve seat 71 of the pilot valve 7.

The float 6 is made of a general float made of foamed nitrile rubber or a plastic hollow float having an automatic drain function, and is slidably disposed on the upper outer periphery of the cylinder 4.
A ring-shaped permanent magnet 12 that operates the pilot valve 7 by repelling the permanent magnet 11 of the pilot valve 7 when the float 6 rises and approaches the pilot valve 7 is attached to the upper inner periphery of the float 6. Has been.
Note that the permanent magnet 11 of the pilot valve 7 and the permanent magnet 12 of the float 6 are ring-shaped anisotropic permanent magnets and are arranged in directions repelling each other, but weak when separated from a specific distance. A suction force is applied.

  Next, the operation of the float drain trap of this embodiment will be described with reference to FIG.

The state of FIG. 1 shows a state where there is no drain and the float 6 is at the lowermost end under a certain pressure.
Since a weak attractive force acts between the permanent magnet 11 and the permanent magnet 12 in this state, and the back pressure also acts on the pilot valve 7, the pilot valve 7 is in a closed state.
Air pressure in the drain case 1 is introduced into the pilot chamber 8 through the filter 10 and the orifice 9, and the pressure on the upper side of the piston 5 is the same as the pressure in the drain case 1.
As a result, the piston 5 has no upward output, and is conversely pushed down by the force of the spring 13 and the back pressure acting on the drain valve 3, and the drain valve 3 is closed.

Next, when the drain flows into the drain case 1 and the float 6 rises, the permanent magnet 11 and the permanent magnet 12 approach each other to generate a repulsive force, and the repulsive force acts on the pilot valve 7. When the back pressure is exceeded, the pilot valve 7 opens instantly.
When the pilot valve 7 is opened, the air in the pilot chamber 8 is discharged to the outside through the pilot valve 7, and the relationship between the discharged air amount and the inflow air amount flowing from the drain case 1 through the orifice 9, that is, Due to the relationship between the effective sectional area of the orifice 9 and the pilot valve 7, the pressure in the pilot chamber 8 becomes lower than the pressure in the drain case 1, and the drain valve 3 is opened by the pressure difference generated between the upper side and the lower side of the piston 5. The drain in case 1 is discharged to the outside.

When the drain is discharged and the float 6 descends, the magnetic force acting on the pilot valve 7 disappears, and the weak suction force acts on the contrary, the pilot valve 7 is closed and air is discharged from the pilot chamber 8. Stops.
Then, when air flows into the pilot chamber 8 from the orifice 9, the pressure in the pilot chamber 8 recovers to the pressure in the drain case 1 and there is no output to the piston 5, whereby the piston 5 is restored, The drain valve 3 is closed and the initial state is restored.

Thus, the float drain trap of this embodiment can indirectly operate the pilot valve 7 by the magnetic force acting between the permanent magnet 11 attached to the pilot valve 7 and the permanent magnet 12 attached to the float 6. In addition, since the repulsive force of the two magnets is proportional to the amount of increase of the float 6, the repulsive force of the magnet gradually increases when the float 6 rises, and the repulsive force reduces the back pressure acting on the pilot valve 7. If it exceeds, the pilot valve 7 opens instantly, and further, the back pressure is reduced by opening the pilot valve 7 and the load on the float 6 is reduced. Therefore, the float 6 further rises, and the snap that reliably opens the pilot valve 7 fully An action function can be provided, whereby stable drainage can be performed over a wide operating pressure range from low pressure to high pressure.
In addition, since this float type drain trap operates the pilot valve 7 indirectly by magnetic force, the orifice 9 and the filter 10 can be provided in the pilot air pressure introduction path upstream of the pilot valve 7. It is possible to prevent the entry of harmful foreign matter into the valve 7, and to eliminate the failure of the pilot valve 7 caused by the entry of the foreign substance.
Further, by arranging the orifice 9 on the upstream side of the pilot valve 7, the diameter of the pilot valve 7 can be reduced to the same level as the orifice 9, and as a result, the float 6 can be reduced.
Also, with the conventional float drain trap, the pilot air pressure control system is limited, so the drain valve system must be the spool valve system, and the spool valve system increases the stroke between the piston and drain valve. Although the drain valve may be damaged in a short period of time, in the float type drain trap of the present invention, it is possible to adopt the poppet valve method because the choice of the control method of the pilot air pressure has increased. In the system, the failure of the drain valve can be reduced because the valve structure is simple and the stroke can be shortened.
In the conventional float drain trap, a mechanism for connecting the pilot valve and the float is necessary. Therefore, the malfunction may occur due to the malfunction of this mechanism. In the float drain trap of the present invention, however, This type of failure can be eliminated because no special mechanism is required.

  As mentioned above, although the float type drain trap of the present invention was explained based on the example, the present invention is not limited to the composition described in the above-mentioned example, suitably combining the composition described in the example, The configuration can be changed as appropriate without departing from the spirit of the invention.

  As described above, the float drain trap according to the present invention prevents the entry of foreign matter into the pilot valve by providing a filter in the pilot air pressure introduction path, and indirectly operates the pilot valve from the outside using magnetic force. Therefore, the operation of the pilot valve has stability and a snap action function, and by arranging the orifice upstream of the pilot valve, the pilot valve has a small diameter and a float as small as possible. Therefore, it can be suitably used for a compact and highly functional drain trap.

It is sectional drawing which shows one Example of the float type drain trap of this invention. It is sectional drawing which shows an example of the conventional float drain trap. It is sectional drawing which shows the other example of the conventional float drain trap.

DESCRIPTION OF SYMBOLS 1 Drain case 2 Discharge port 21 Valve seat 3 Drain valve 4 Cylinder 5 Piston 6 Float 7 Pilot valve 71 Valve seat 72 Exhaust pipe 8 Pilot chamber 81 Communication path 82 Small chamber 9 Orifice 10 Filter 11 Permanent magnet 12 Permanent magnet 13 Spring 14 Filter cover 15 Packing

Claims (1)

A drain valve (3) for opening and closing the discharge port (2) of the drain case (1) is attached to the piston (5) accommodated in the cylinder (4), and a spring (13) is attached to the piston (5). A pilot valve mechanism that opens and closes the drain valve (3) by applying a pilot air pressure in addition to the force is provided, and the pilot valve mechanism is moved by a lifting and lowering operation of the float (6) disposed outside the cylinder (4). In the float drain trap adapted to open and close the pilot valve (7), when the pilot valve mechanism is opened by opening and closing the valve seat (71) disposed in the pilot chamber (8), A pilot valve (7) for discharging the air in the pilot chamber (8) through the exhaust pipe (72) by communicating the pilot chamber (8) with the outside of the drain case (1); It is formed on the upstream side of the pilot valve (7), orifice and communicating with an internal drain bowl (1) pilot chamber (8), introducing the pressure of the drain bowl (1) in the pilot chamber (8) ( 9) and a filter (10) attached to the upper portion of the orifice (9), a permanent magnet (11) is attached to the pilot valve (7), and the float (6) In a state where the float (6) is at the lowermost end, an attractive force acts between the permanent magnet (11) located below the permanent magnet (11) of the pilot valve (7), and the pilot valve (7 ) biased in closing direction, the float (6) is increased, the repulsive force between the permanent magnet approaching from below the permanent magnet (11) of said pilot valve (7) (11) act To open the pilot valve (7) instantly Float drain trap, characterized in that it has attached a permanent magnet (12).

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